The PetCell by PetsMobility Inc.

My girlfriend's dog ran away when she was in high school, and she still talks about it from time to time -- in her late 20s.
Lesson is: don't lose your dog, you'll never get over it.
Hence, I think this dog cell -- while it might, at first, seem a little silly -- is actually quite ingenious. At the very least, it's better than paying to implant some chip in Fido's butt.